Learn Free Civil Engineering by Civilustaad ; What is The moment of inertia?

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THE MOMENT OF INERTIA

The moment of inertia, or else known as the angular mass or rotational inertia, of an inflexible body determines the torque needed for a preferred angular acceleration about a rotational axis.   

 It depends on the body's mass distribution and the axis selected, with larger moments requiring extra torque to change the body's rotation.

 It is an wide-ranging (additive) property: the moment of inertia of a composite system is the sum of the moments of inertia of its part subsystems (all taken about the same axis).

One of its definitions is the second moment of mass with respect to distance from an axis r, I = \int_m r^2 \mathrm dm , integrating over the whole mass.

For bodies inhibited to rotate in a plane, it is enough to consider their moment of inertia about an axis perpendicular to the plane. 

For bodies free to rotate in three dimensions, their moments can be described by a symmetric 3 × 3 matrix; each body has a position of mutually perpendicular principal axes for which this matrix is diagonal and torques around the axes act separately of each other.

Learn free Civil Engineering by Civilustaad ; An useful info about Soldier piles and lagging

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SOLDIER PILES AND LAGGING

Soldier piles and lagging is a ground retention method that retains soil, by vertical steel piles with horizontal lagging. Characteristically, H-piles are drilled or driven at usual intervals along the planned excavation perimeter.

There use is increasing day by day in modern Civil Engineering works because of certain advantages. Different inventions are being done to improve site related issues.

Learn Civil Engineering by CivilUstaad ; A detail about Wick Drain ; An informative work

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WICK DRAINS

Wick drains, also identified as Prefabricated Vertical Drains (PVD) and Vertical Strip Drains (VSD), are a ground improvement method that provides drainage paths for pore water in soft compressible soil, using prefabricated geo-textile filter, wrapped plastic strips by molded channels.

Wick is a Dutch company expert in soil stability, including installation of Prefabricated Vertical Drain (PVD). They have world biggest PVD Installation rig, which can put in up to 60m. PVD manufacturers are Ceteau, Tencate, etc. 

Learn free Civil Engineering by Civilustaad ; An useful info about BEAMS WITH DUCTILITY

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BEAMS WITH DUCTILITY

Ductility is a enviable structural property since it allows stress redistribution and provides caution of impending failure.

Steel-reinforced concrete beams are under-reinforced by design, so that malfunction is initiated by yielding of the steel reinforcement, followed after substantial deformation at no substantial loss of load carrying capacity, by concrete crushing and ultimate failure. This form of failure is ductile and is guaranteed by designing the tensile reinforcement ratio to be considerably below (ACI 318 requires at least 25 % below) the fair ratio, which is the ratio at which steel yielding and concrete crushing occur concurrently. The reinforcement ratio thus provides a metric for ductility, and the ductility corresponding to the maximum allowable steel reinforcement ratio provides a gauge of the minimum acceptable ductility.

The design of FRP external reinforcement for flexure is quite rational and simple. It is based on Bernoulli’s theory of strain compatibility that plane sections remain plane, which requires ideal bonding between FRP and concrete, and the capability of the concrete to transfer stresses to the FRP laminate by shear. In a beam reinforced inside with steel and externally with FRP, there is typically substantial reserve capacity at steel yielding. After the steel reinforcement yields, the beam can still carry increasing loads, although at a lower rate (with respect to deflections) than prior to steel yielding, and the FRP maintains elastic behavior until failure occurs suddenly. Failure is precipitated by FRP de-bonding, rupturing, or concrete crushing. Every of these modes of failure are brittle, i.e., load capacity is reached with modest inelastic deformation.

Free Learn Civil Engineering by Civilustaad ; Wet Soil Mixing basic info with video explanation

WET SOIL MIXING, ALSO KNOWN AS THE DEEP MIXING METHOD

Wet soil mixing, also recognized as the Deep Mixing Method, is a ground improvement method that improves the distinctiveness of weak soils by mechanically adding them with cementitious binder slurry. To build columns, a powerful drill advances drill steel with radial mixing paddles located near the bottom of the drill string. The binder slurry is pumped through the drill steel to the tool as it advances and supplementary soil mixing is achieved as the tool is withdrawn. To perform mass wet soil mixing, or mass stabilization, a horizontal axis rotary mixing tool is located at the ending of a track hoe arm. 

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Free learn Civil Engineering by Civilustaad; AUGER-CAST PILES basic info

AUGER-CAST PILES

Auger-cast piles, too identified as continuous flight auger piles (CFA), are deep foundation elements that are cast-in-place, using a hollow stem auger with uninterrupted flights. The auger is drilled into the earth and/or rock to design depth. The auger is then gradually extracted, removing the drilled soil/rock as concrete or grout is pumped all the way through the hollow stem. The grout pressure and volume should be carefully controlled to construct a continuous pile exclusive of defects. Reinforcing steel is next lowered into the wet concrete or grout. The completed foundation element resists compressive, uplift and lateral loads. The method has been used to carry buildings, tanks, towers and bridges.

Free learn Civil Engineering by Civilustaad ; A detail about procedure and advantages of LAMINATE FLOORING

LAMINATE FLOORING

Laminate flooring has numerous advantages over other flooring options, such as hardwoods, tile or stone. It is extremely durable, easy to clean and installs speedily. Actually, most DIYers can complete an entire room in one day. Planks can be cut with a hand saw or circular saw, so no particular tools are required. Most laminate systems have planks that merely snap jointly with a tongue-and-groove system.

An underlayment is requisite before laying the planks in position. Some laminate products come with an underlayment previously attached. If the product you selected doesn't, roll out a layer of it individually as you go.

The flooring doesn't have to be glued down. The floor floats on the underlayment and is held in position by the quarter-round moldings installed on the edges.

Its form is really just an image applied to the surface of the plank, so it can be manufactured to give the look of different hardwoods, tile and stone. It can be installed in roughly every room in your home, because it can be installed above wood or concrete subfloors.

When shopping for laminate flooring, compute the room's length and width to work out the amount of product needed. Remember to add 10 percent to the whole to permit for any waste or missed cuts.

Free learn Civil Engineering by Civilustaad ; FLOWER" fountain construction at the Seaside National Park.

FLOWER" fountain construction at the Seaside National Park.

"FLOWER" fountain has been installed in the sea at a space of 600m from the beach in the National Park. Fountain is feed through 630mm diameter pipe laid on the sea-bed. The pump station installed on the beach squeeze water under the pressure of 20 bar the water pumps out of the nozzle, which is 120mm in diameter and rises to the height of 140m. 
The pipe-line which is 600m long has been welded on the beach. 14 auto-cranes with the lifting power of 50 tons participated in the elating the pipeline into the water. WWW.DIZEL.AZ website's services were used for managing the lifting operation at the same time.
The pipeline was tugged to the projected position and installed on the seabed.

Soil erosion and settlement often cause concrete slabs to sink into the ground

Soil erosion and settlement repeatedly cause concrete slabs in patios, sidewalks and driveways to sink into the ground. This type of settlement isn't just unattractive; it can also cause added damage and can be a safety hazard. Water tends to pool on sunken surfaces and un-leveled  floors cause a trip hazard. 

Until now, the lone solution on hand to repair sinking slabs was mud-jacking, a procedure that involves drilling holes in the slab to inject a mixture of cement and mud underside, to raise it back to level.

What is Dynamic Compaction; a useful info

DYNAMIC COMPACTION

Dynamic compaction is a method that is used to augment the density of the soil when definite subsurface constraints make other methods unsuitable. It is used to boost the density of soil deposits. The process involves of dropping a heavy weight frequently on the ground at repeatedly spaced intervals. The weight and the height decide the amount of compaction that would take place. The weight that is used depends on the degree of compaction desired and is between 8 tone to 36 tone. The height varies from 1m to 30m.

The impact of the free fall creates stress waves that assist in the densification of the soil. These stress waves can go through up to 10m. In cohesionless soils, these waves generate liquefaction that is followed by the compaction of the soil. In cohesive soils, they generate an increased amount of pore water pressure that is followed by the compaction of the soil. Pore water pressure is the pressure of water that is intent within the particles of rocks and soils.

The amount of compaction depends on the weight of the hammer, the height from which the hammer is dropped, and the spacing of the locations at which the hammer is dropped. The initial weight dropping has the majority impact, and penetrates up to a larger depth. The following drops, if spaced closer to one another, dense the shallower layers and the process is completed by compacting the soil at the surface.

Most soil types can be enhanced with dynamic compaction. Old fills and granular soils are most frequently treated. The soils that are underneath the water table have to be treated cautiously to allow emission of the excess pore water pressure that is formed when the weight is dropped onto the surface.

Info about CRITICAL PATH METHOD with examples.

CRITICAL PATH METHOD

 
Purpose:

Project manager and stakeholders are capable to identify responsibilities which are critical, i.e. if delayed will cause overall project delay, or on the opposing has the likely of reduction project implementation time. Ability to recognize these tasks will permit project manager and stakeholders to develop strategies during project implementation in order to attain effectiveness and efficiency. 

B. Usage

This tool is very helpful in project implementation and monitoring period, particularly during project progress evaluation

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•Identify critical activities and path. Critical activity is the activity which has zero or less than zero (minus) slack/float. It means that if project wants to complete on time, as much as likely avoid delays on critical activities since this will cause delays on the overall project duration.

Critical path is the pathway of decisive activities, i.e. activity which has slack/float 0 or less than 0. In this instance, the critical path is Activity 1, Activity 2 and Activity 5. Delay ought to be avoided in these activities, since it will cause delay in overall project completion. Activities 3 and 4 are more flexible; however project stakeholder should pay consideration to the latest finish of these activities to avoid pressure to next critical activity, Activity 5.

What are basics of beam in Structure?

What are basics of beam in Structure?

Structures for instance buildings and bridges consist of a number of components for example beams, columns and foundations all of which act jointly to ensure that the loadings that the structure carries is securely transmitted to the supporting ground below.

Usually, the horizontal beams can be made from steel, timber or reinforced concrete and have a cross sectional form that can be rectangular, T or I shape. The design of such beams can be difficult but is essentially intended to ensure that the beam can safely carry the load it is anticipated to support. This will comprise its own self-weight, the weight of the structure it is supporting and what is often referred to as live load, i.e. the weight of people and furnishings in buildings or the load of road or rail traffic in bridges.

How Structural repairs are done; A video explanation

Structural repairs:

Structural repairs are made simple using brick reinforcement comprising helical bars form Twist fix. Stainless steel reinforcing bars are grouted into brickwork to outline a reinforced brick beam or wall lintel. The masonry repair reinforcement represents the upper and lower flanges of a deep masonry beam to form a wall lintel and to support brickwork over the window opening.